(1) Field of the Invention
The present invention relates to a protective device for protecting an occupant of a vehicle, to a seat, and to an associated vehicle. It relates more particularly to an aircraft, such as a rotary-wing aircraft.
(2) Description of Related Art
In particular, airbags are known that inflate when an impact occurs to protect an occupant of a vehicle.
Such airbags may be installed in dashboards, in seats, or in partitions defining the spaces for accommodating the occupant to be protected. As described in Document EP 1 616 760, it is also possible to provide reusable airbags in seatbelts, for example.
It is common for motor vehicles to have such airbags. Aircraft and in particular rotary-wing aircraft also sometimes have airbags.
Airbags make it possible to reduce the forces to which occupants of a vehicle are subjected during an accident in order to preserve their physical integrity. In addition, airbags limit the extent to which the heads of occupants of the vehicle move, and form barriers against impacts with the members of the vehicle that become potentially dangerous during such accidents.
However, an aircraft might have to make an emergency landing on a liquid surface, i.e. it might have to ditch. Certain emergency landing or ditching scenarios can require an airbag to be deployed for a non-negligible duration, rather than merely at a particular instant.
Deploying an airbag over a relatively long duration following a ditching on water raises a potential difficulty. There is a non-zero risk that the space surrounding an occupant of the aircraft might fill with water. The airbag can then constitute a major obstacle that needs to be overcome so that the occupant can exit from the aircraft before going under.
Documents U.S. Pat. No. 5,857,246 and U.S. Pat. No. 6,930,611 disclose devices suitable for opening a seatbelt buckle or seat harness buckle on coming into contact with a liquid.
Documents U.S. Pat. No. 4,498,604 and U.S. Pat. No. 4,260,075 disclose a device for inflating an article, such as a life jacket, on coming into contact with a liquid, that device involving a member that is soluble in water.
Document U.S. Pat. No. 6,024,116 also discloses such a device in a field remote from the problem to be addressed, namely the technical field of boilers.
In addition, it should be noted that Document U.S. Pat. No. 6,378,898 mentions the use of a system for deflating an airbag after a predetermined lapse of time.
Document EP 1 418 093 describes an airbag co-operating with inflation means. In addition, the described device is provided with a vent and with a tube, and with means for retaining the tube.
Finally, Document JP 11170963 would appear to describe a device for preventing an airbag from being triggered when in the presence of water.